His eyes were closed, he was bleeding from the mouth, mostly from the sinuses, and he was unable to stand. His injuries pointed to head trauma, most likely caused by a high-speed collision with a glass window on the building above the station. The bird was given vitamin K injections to stop internal bleeding and placed in a warm, dark enclosure to recover.
At first, he simply lay still, and we worried that he would not be able to survive his injuries. But with subcutaneous fluids and rest, the next day he was lifting his head and making eye contact, and on the next, standing and flapping his wings.
We put him on solid food. We had to hand-feed him in the beginning, but he soon became a big fan of defrosted mice and would charge the door of his cage when we brought his meals, which he had no problem eating on his own. In ten days, he gained one third of his initial body weight.
The red-tail also recovered from his head trauma, and his vision, which he relied on for hunting, had not been permanently damaged. He could be released back into the wild.
A pair of red-tails were circling over Central Park the day we brought our hawk out to the release site. We opened the box on a small hill far from the other hawks, which tend to be territorial, and waited as our patient looked out over the wide expanse. A park vehicle rumbled by. We waited. The distant din of the city streets rose and fell. We waited. He looked around some more. We waited.